This project entails the development of an accessible, sensitive, , and reliable method of detecting domoic acid in aqueous media. This compound is a potent phytotoxin that acts as agonist to ionotropic glutamate receptors (iGluR) in the central nervous system and has recently threatened public health and the fishing industry. The detection method will be based on a synthetic receptor tailored to bind domoate molecules labeled with a fluorophore probe, dansyl. The receptor will consist of a dendritic matrix affixed to polystyrene beads. This matrix is designed to engulf a pre-cognitive binding site which is composed of short peptide sequences closely positioned to interact with the targeted neurotoxin. The peptide sequence with highest affinity for the substrate will be selected from a receptor library developed by combinatorial methodology.